FLIES THE ILY

NEW GENERA OF TWO-WINGED FLIES OF THE SUBFAM- ILY LEPTOGASTRINAE OF THE FAMILY ASILIDAE.

By

J.

M.

Aldrich,

Associate Curator, Division of^Insects,UnitedStatesNationalMuseum.

The

present paper is intended primarily to publish a remarkable

new

genus of fly in

which

the basal half of the

wing

is reduced to a slender hairlike stalk. In the study of related forms, however, it

appeared that several

new

genera of the

same

subfamily are in the United States National

Museum

collection,

and

these

have

also

been

included, with a table of genera.

The

subfamily Leptogastrinae is readily separated

from

other Asilidaein

America by

having the pulvilliabsent, the

empodia

^either absent or reduced to a central almost straight claw, about

haK

a long as the other claws;

abdomen

slender

and

elongated; marginal

cell open, analangleof

wing

undeveloped,

and

cellwideopen. Inthe old world various connecting genera occur without pulvilli. I

have

included one such

American

genus, Caenarolia

Thomson,

inthe pres- ent paper; it is shorter

and

stouter than the other included forms,

and

has the anal angle normallydeveloped.

TABLE OFAMERICAN GENERA.

1. Wingsuncommonlynarrowat base,theseventh vein absent 2

Wingsnormal, seventh veinpresent 3

2. Wing with basal half reduced to a hairlike pedicel, the auxiliary and ^first veins fusedwiththecosta(CostaRica) Eurhabdus,new^genus.

Wingnot withslender hairlike basal half, auxiliary and ^first veins present

(Brazil) LeptopteromyiaWilliston.

3. Mesonotum withapair of erectdorsocentral bristles, anterior to themiddle;

veins hairy (Costa Rica) Schildia, newgenus.

Mesonotumwithoutdorsocentrals(withonepairsupraalarsandonenotopleural) 4 4. Antennalstyle minute, hardly visible; wings longer than abdomen (Brazil)

CaenaroliaThomson.

Antennalstyle at leasttwo-thirdsaslongas thirdantennaljoint 5 5. Empodiaentirelyabsent (widespread) Psilonyx, newgenus,

Empodiapresentasamedianclaw abouthalf aslongasthe other claws (wide-

spread) LeptogasterMeigen.

No.2466.-PROCEEDINGS U.S. NATIONALMUSEUM. VOL.62, ART.20.

1

2 PROCEEDINGS

OF

THE

NATIONAL,

MUSEUM.

vol.62.

EURHABDUS,

newgenus.

Most

of the generic characters are well

shown

in the figure.

The wing

^is greatly reduced in venation.

The

auxiliary

and

first longi- tudinal veins are entirely absent; the third vein originates directly in the costa,

which

is not especially enlarged; the discal cell is wide

open

to the margin; the fourth vein is unbranched; there is

no

^777777

Figs.1-2.—_1, Eurhabdus zephyreus,newgenus andspecies,type specimen. Muchenlarged.

2, Wingofsame, more enlarged. Drawnby R. E. Snodgrass.

seventh vein.

The

basal portion of the

wing

for almost exactly one-half of the length is reduced to an exceedingly slender hairlike stalk

which

has afew delicate cilia on both sides.

The

antennae are very small

and

there is a slender subdorsal arista instead of the two- jointed thick style occurringinLeptogaster.

The head

isnotgreatly flattened, almost as large as the thorax; the latter being

somewhat

moldy, it is impossible to tell whether it originally

had any

bristles

ART.20.

NEW GENERA OF LEPTOGASTRINAE

ALDEICH. 6 ornot.

The empodia

are slightly developed in the

form

of a middle claw

which

is about one-third aslong as the outerones.

Genotype.

—

_{Eurhabduszeyhyreus,}

_new

_species.

EURHABDUS ZEPHYREUS,newspecies.

Female.

—

^{Shiningblack; the orbits}

^and

^{pleurae with white pollen;}

the front

and

middle ^legs, except the coxae, pale yellow; hind legs yellow except the clubbed ^apical fourth; hind tibiae yellow; the apical third black

and

considerably swollen; hind tarsi black;

haltereslong

and

slender, yellow,witha shining blackknob.

Length, 6.2

mm.

Described

from

one female collected at Higuito,

San

Mateo, Costa Rica,

by

Pablo Schild.

Iiype.—Female, Cat. No. 25307, U.S.N.M.

Inorderto bringoutasclearly as possible theremarkablereduction

which

the venation in this species has undergoneI

have had

afigure prepared ^(fig. 3) of the venation of the type species of Leptogaster in

which

dotted lines areused to indicate the veins

which

are absent in Eurhabdus.

Fig.3.—WikgofLeptogastee cylindrica. The veins indicatedby dottedunes are absent IN Eurhabdus. Drawn by CharlesT. Greene.

Genus

LEPTOPTEROMYIA

Williston.

LeptopteromyiaWilliston,ManualofNorthAmericaDiptera, ed. 3,p. 195, 1908.

Thisgenus exists only

by

virtueof a

named

^{figure in} oneof Willis- ton's plates.

The

type species is L. gracilis Williston,

named,

but not described, on the

same

page,

and

said to be

from

Brazil.

The head

of thespecimenis notfigured

and

probably

had

been broken off.

The

general appearance ^is precisely that of Leptogaster except that there is apparently

no empodium and

the

wing

is

much

narrower on the basal half.

The

figure

shows

a

normal

discal cell,

no

seventh vein, first veinpresent,

and

probably the auxiliary.

The

species can

in ail probability be recognized without difficulty

from

the figure

when

rediscovered.

The

location of the typespecimen atthe present time ^is

unknown.

4 PROCEEDINGS

OF

THE NATIONAL MUSEUM.

^vol.ez.

SCHILDIA,newgenus.

Differs

from

all the other

members

of the

group

in having hairy veins

and

a pairofdorsocentralbristles near together before themid- dle of the

mesonotum.

Venation as in Leptogaster, the first vein, however, running parallel with the costa

around

the curve almost to the extreme

apex

ofthe wing.

Genotype.

—

ScMldia microthorax,

new

species.

Named

ⁱⁿ

^honor

^ofPablo Schild, oneof the best tropical collectors ofsmall Diptera.

SCHILDIA MICROTHORAX,newspecies.

Male and

female.

— Antennae

yellow, the third joint brown, not

much

elongated with subapical slender style

which might

be called

an

arista.

Head

black, proboscis brown.

Mesonotum

shining, brownish yellow, extending forward with a considerable

hump and

bearingadistinct

median brown

stripe

which

doesnot reachthescutel- lum.

The

characteristicpairofdorsocentralbristles arevery evident

and

in addition there are the

two

usual pairs, onesupraalar, theother notopleural. Pleuraepale yellow above,

brown

below; the thorax is

only a little larger than the head, Halteres elongated

and

slender, pale yellow with a shining black knob.

Abdomen

very slender, blackish; the second joint

brown

with a yellow ring in the middle;

second

segment

of the

abdomen

aslong as the

wing

to the fork of the thirdvein or a little longer. In the

male

this is

much

less than one- half the entire length of the

abdomen;

in the female, however, it is a httle

more

than one-half the entire length. Front

and

middle legs

and

all the coxae yellow; hind legs brownish-yellow with a blackish tip precededwithayellow ring

which

is

on

the beginningofthe swol- len portion; hind tibae brownish-black; hind tarsi brown. All the tarsi in both sexes are destitute of

empodia and have

the outer claw twice as long as the inner one.

Wings

hyaline, glabrous except the veins,

which

are distinctlyhair}^.

The

costa is ciliated

from

near the base to the

apex

with noticeablyfine

and

densehairs; the outer vein curves

backward

^{so as} to end almost exactly in the

apex

of the wing.

The male

genitalia are very small, the visible portion consisting of a pairof smallcurved

brown

processes projecting directlybackward.

Length

ofmale, 8.4

mm,,

offemale, 5.9

mm.

Described

from

one

male and

one female collected at Higuito,

San

Mateo, CostaRica,

by

PabloSchild,

Type.—

Male,

and

allotype, female. Cat,No. 25308, U.S,N,M.

AKT.20.

NEW GENERA

OF

LEPTOGASTRINAE

ALDRICH. 5 PSILONYX, new genua.

Differs

from

Leptogaster only in the complete absence of empodia.

Genotype.

—

Leptogasterannvlatus Say.

PSILONYX ANNULATUS^Say.

Leptogaster annulatus Say, Journ. Acad,of Nat.Sci., vol.3, p. 75, 1823; Complete Works,vol.2, p.G8.—Back,Trans.Amer.Ent. Soc,vol. 35, p. 159, 1909.

In

making

thisspecies the type of a

new

genus I

am

carrying out, after the lapse of a century, a suggestion

made by Say

in his original publication, as follows

:

Thenervuresofthewingsof this insect, donot perfectly correspondwiththoseof L.tipuloides,whichcircumstance,combinedwithanother highlyimportantdifference thatthis insect exhibits, inhaving buttwonails tothetarsi,wouldjustifythe generic separationofthe annulatusfromthetipuloides,anditsreferencetoadistinctgenus.

Specimens intheAvxiter's collection

from Ecuador

do not

seem

to be distinct

from

others collected at Lafayette, Indiana. There are,

however,

some

additional tropical species

which

can not at present be elucidated^;

and

Mr.

Back

has described a second species

from

the United States, P. schaefferi

from

Brownsville, Texas.

Genus

LEPTOGASTER

Meigen.

LeptogasterMeigen, Illiger'sMagazin,^vol. 2, p. 269, 1803;Systematische Beschreib., vol. 2, p. 258, 1820,

Gonypes Latreille, Ilistoirenat. Crust, etIns., vol. 14,p. 309, 1804.

LeptogasterBack,Trans.Amer. Ent. Soc, vol. 35, p. 155, 1909.

TipulogasterCockeuell, The Entomologist, vol. 46, p. 213, 1913.

In the originaldescription

Meigen mentioned

onlyAsilustipuloides Fabricius,

which

is

now

regarded as a

synonym

of Asilus cylindricus DeGeer.

The

type of Gonypes is also tipuloides.

The

type ^of

Tipulogasteris hadius

Loew.

There

are

many

species of this genus,

which

appears ^to be wide- spread in the Eastern

and Western

Hemispheres, both in tropical

and

temperate regions.

Genus

CAENAROLIA

Thomson.

Caenarolia Thomson, Kongliga Svenska Fregatten Eugenies Resa Omkring .Torden, vol. 2, Zoology No. 1, p. 470, 1868.

Acronyches Williston, Manual ^ofNorth American Diptera, ed.3, p. 388, 1908.

Thomson

^{described this genus}

^from

^{a single}

new

species

which

he called longipennis. It

was from

Rio Janeiro.

He

refers to miles

Wiedemann

as belonging to the

same

genus, but gives

no

description of it.^

Wiedemann's

description of miles is so brief that it isevident that

Thomson must have

seen thetypeor

he

couldnot

have

assigned

'DasypogonmilesWiedemann,Aussereuropaische ZweifliigeligeInsekten, vol. 1, p. 393, 1828,from Brazil.

6 PEOCEEDINGS OF THE NATIONAL UNION.

^vol.62.

it to this genus. Williston figures a species

which

appears to agree exactlywithlongipennis except that the fourth posterior cell is

open

while it is closed before the

margin

in

Thomson's

species.

He men-

tioned this genus in this connection becauseit has no

empodia and

has

many

characters in

common

with Leptogaster.

However,

the

normal development

of the anal angleof the

wing and

^especially the

form

of the analcell,

which

is almost closed in themargin, indicates a considerable divergence

from

the Leptogaster type.